The invention relates to a face equipment for mechanical extraction in longwall mining, in particular in the underground hard coal mining industry, with a face conveyor arranged along the mining wall, an extraction means that can be moved along the face conveyor, and shield support frames supported on the face conveyor at an angle thereto.
WO 2009/103303 describes a face equipment with the aforementioned features along with a method for controlling such a face equipment. To this end, the above publication explains in detail that automating such a controller for the face equipment generally depends on knowing where the face equipment is positioned in the room, but especially on knowing the respective height of the face opening that exists in the region of the front end of the roof canopy of the shield support frame. The respective base values for calculating the face opening height are determined in this prior art by means of inclination sensors secured to the main components of the shield support frame, such as the floor skid, gob shield, support connection rod and roof canopy, which determine the inclination of the respective components against the vertical. By comparing the recorded data with base data that are stored in an evaluation unit and define the geometric orientation of the components of the shield support frame and its movement while advancing, the respective height perpendicular to the stratification can be calculated for the shield support frame at the front end of its roof canopy, which represents a gauge for the height of the face opening.
The known procedure is associated with the disadvantage of complex computing operations, which further require that the base data valid for the respective design of the used shield support frame be accurately determined, and that a useable algorithm be generated for calculating the height perpendicular to the stratification of the shield support frame.
Apart from indirectly determining the height of the face opening mentioned above, a method for directly ascertaining height data by means of a flexible hose level system while boring tunnels is known from DE 43 33 032 02. Situated between the tunnel boring machine and a reference point here is a flexible hose level system, whose closed, liquid-filled hose is allocated to the reference height at one end, and to the tunnel boring machine at the other end for determining additional measuring height dimensions for the tunnel advancing machine.